Characterization and Application of New Natural Hydraulic Lime Produced from Lime Mud

摘要

A new natural hydraulic lime (NHL) has been fabricated from lime mud and 5-15% by weight fly ash by calcination and it has been applied to the preparation of fly ash bricks. Lime and dicalcium silicate have been identified as the main crystalline phases of the new NHL by X-ray diffraction (XRD) analysis. Tricalcium aluminate and gehlenite were formed when fly ash content was increased. After calcining at l,000℃, available lime (31-55% by weight) and sulfate (0.53-0.71% by weight) contents of the new NHL have conformed the performance requirements of NHL. Compressive strength of standard mortars showed that the new NHL met performance requirements. Results also showed that for the new NHL, 900-1,000℃ was chosen as the optimum calcination temperature and 10% by weight was the optimum fly ash content. Comparison of the compressive strength of fly ash bricks with the new NHL and ordinary lime has indicated that the new NHL shows better behavior than ordinary lime. Moreover, fly ash bricks with the new NHL have high compressive strength in water curing (5.8-19.7 MPa), natural curing (8.5-20.5 MPa), and autoclaved curing (17.4-22.5 MPa) conditions.